The present invention relates to a protection module for protecting a subscriber circuit of an exchange from an overvoltage or an overcurrent.
The recent electric exchange requires the function of BORSCHT(Battery feed, Overvoltage protection, Ringing, Supervision, Coding, Hybrid, Test access) for analog subscriber interface and have implemented the analog subscriber interface circuit as the semiconductor integrated circuit (SLIC IC). The conventional overvoltage, overcurrent protecting devices could not protect completely the electric exchange because this SLIC IC has inferior durability for the overvoltage and overcurrent than that of the transformer of the mechanical exchange.